Electron discharge device



Aug. 3, 1943. H. COHN ELECTRON DISCHARGE DEVICE Filed Dec. 2, 1941uninvi- 11141111 INVENTOR. HENN Y COl/N ATTORNEY.

Patented Aug. 3, 1943 nnnc'mou DISCHARGE nnvron Benny Cohn, Eindhovcn.Netherlands vested in the Alien Property Custodian Application December2, 1941. Serial No. 421,287

In the Netherlands April 9, ,1940

Claims.

My invention relates to electron discharge devices, more particularly tosuch devices useful as a converter in superheterodyne circuits.

This invention relates to improvements in a circuit comprising a tubewhose electrode system is formed by a cathode, an anode and at leastfive intermediate electrodes of which the first two constitute theoscillator electrodes and in which the oscillator anode is constitutedby a few rods or plates which also ensure a uniform electrondistribution, and the third electrode from the cathode is also rod orplate-shaped. Around these electrodes in turn may be the second controlgrid. a screen grid and a suppressor grid. The invention also relates toa tube of this kind.

In one form of prior construction of the tube and circuit, theoscillator anode which is given a positive potential relatively to thecathode is constituted by a few rods located at the corners of arectangle or a square. An oval-shaped or round electrode systemasdisclosed in the accompanying drawing is used. This has givensatisfactory results. A few more rods can be arranged on the longersides of the rectangle but according to the invention it has been foundthat it is not advantageous to use further rods at a comparatively highpositive potential, arranged on the shorter sides.

According to the invention, it has been found as a matter of fact thatin this electrode construction it is in some cases desirable that theelectrons which during operation of the tube may return from in front ofthe second control grid should reach the rod-shaped oscillator anodedirectly and not oscillate back and forth around these rods and bringabout so-called Barkhausen oscillations. Barkhausen operation does notrender the tube well adapted for use in superheterodyne circuits. 1

Now, this difliculty is obviated by the use of a circuit and a tubeaccording to the present invention in which rodor plate-shaped elementsare arranged immediately adjacent the plane of the oscillator anodebetween the rod-shaped elements of this anode and substantially in aplane passing through the cathode and the third electrode following thecathode. said elements being connected to a point of low potential, forexample zero potential. It is thus ensured that the electrons whichreturn in front of the second control grid no longer oscillate aroundthe rods of the oscillator anode but, due to the presence of electrodeparts placed at a low potential and arranged immediately adjacent thesaid ositive rods, reach the latter. In addition, ahighly favorableelectron distribution for the second control electrode is obtained bythis combination of rods.

Various forms of construction of a tube according to the presentinvention are possible; thus, for example, two rods may be arrangedimmediately adjacent the plane of the oscillator anode, said rods beingconnected insideor outside the tube either to the control grid or to thethird electrode following the cathode or again to the cathode itself. Avery practical form of construction consists in connecting the rods andthe third electrode from the rods to form a hairpin-shaped body. It is,however. also possible to unite the said electrodes to form a singleelement by arranging small narrow plates between the plane of the secondand the third electrodes instead of interconnecting two rods.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims, but theinvention itself will best be undertsood by reference to the followingdescription taken in connection with the accompanying drawing in whichFigure 1 is a schematic top end view of an electron discharge devicemade according to my invention and Figure 2 is a schematic of the tubein Figure 1 and its associated circuit made according to my invention.

In order that the invention may be clearly understood and readilycarried into effect it will now be described more fully with referenceto the accompanying drawing, in which the electrode system of a tubeaccording to the present invention is illustrated diagrammatically inFigule 1. In this tube 8. directly heated cathode I is surroundedentirely by the first control grid 2. The oscillator anode isconstituted by four rods 3, immediately adjacent the plane of thiselectrode are arranged two rods 4 which are connected to the rods 5 ofthe third electrode. which, as in a tube according to the priorspecification, serves to compensate the capacities, and to the firstcontrol grid. Instead of being united by interconnecting rods theelectrodes 4 and 5 may be united to form small narrow plates whichextend in the space between the planes of the electrodes 3 and 4.Lastly, there are in the tube a number of grids 6, I and a and an anode9. The connection between the rods 4 and 5 and the grid 2 is representeddiagrammatically by In and the connection of the suppressor grid 8 tothe cathode l is diagrammatically illustrated by H. These variousconnections may be arranged inside or outside the tube. Althoughdivergent voltages may be placed on the various electrode parts it hasbeen found by the applicant that favorable results are obtained if theelectrode 3 is given a voltage of the order of magnitude of 60 voltsrelatively to the cathode and, if the rods 4 are connected to theelectrode 5 and the oscillator control grid 2, the potential of theseelectrodes relatively to the cathode may be of the order of magnitude of'75 volts.

In Figure 2 is shown the electron discharge device made according to myinvention incorporated in its associated circuit.

As there shown the oscillator grid 2 is connected to the oscillatorcircuit l4 through a condenser l5 and resistor is. The anode electrodes3 are connected to the primary I4 of the transformer for providingfeedback to the oscillating circuit l4. The electrodes 2 and 3 with theoathode l constitute the local oscillator electrodes. The auxiliaryelectrodes 4 and 5 are electrically connected back to the grid 2. Theinput circuit I3 is coupled to the antenna by means of the transformer12, the grid 6 being connected to one side of the input circuit [3. Thescreen grid 1 is biased by a positive-voltage source and the suppressor8 tied back'to the cathode, the output being taken from the outputcircuit l1 coupled by means of transformer l8 to a load.

While I have indicated the preferred embodiments of my invention ofWhich I am now aware and have also indicated only one specificapplication for which my invention may be employed, it will be apparentthat my invention is by no means limited to the exact forms illustratedor the use indicated, but that many variations may be made in theparticular structure used and the urpose for which it is employedwithout departing from the scope of my invention as set forth in theappended claims.

What I claim as new is:

1. An electron discharge device having a cathode surrounded by a firstcontrol grid and an anode, oppositely disposed electrodes positioned onopposite sides of the cathode and between the control grid and anode anda second control electrode surrounding said cathode, first control gridand oppositely disposed electrodes, and auxiliary electrodes positionedbetween the oppositely disposed electrodes and the second controlelectrode and adapted to be maintained at a potential not greater thanthat of the first control electrode during operation of the electrondischarge device.

2. An electron discharge device having a cathode surrounded by a firstcontrol grid, a second control grid and an anode, a pair of oppositelydisposed anode electrodes positioned between the first and secondcontrol grids, and auxiliary electrodes positioned between the anodeelectrodes and the second control grid and electrically connected to thefirst control grid, and comprising a pair of rods lying in a planepassing through the cathode.

3. An electron discharge device having a cathode, a control gridsurrounding said cathode and having a pair of oppositely disposed siderods, a second control grid surrounding the first control grid andprovided with oppositely disposed side rods lying in the same plane asthe side rods of the first control grid, a screen grid and an anodesurrounding said cathode and control grids, oscillator anode electrodescomprising rod-like elements positioned between the first and secondcontrol grids, and auxiliary electrodes positioned between theoscillator anode electrodes and said second control grid, said auxiliaryelectrodes .ly-

ing in a plane passing through the side rods of said control grids, eachof said oscillator anode electrodes comprising rod-like elements lyingin a plane transverse to the plane passing through the. control gridside rods.

4. An electron discharge device having a cathode comprising a pluralityof filaments lying in a common plane, a pair of control gridssurrounding said cathode, the first control grid having a pair of siderods lying in a plane passing through said cathode filaments, an anodesurrounding said cathode and control grids, oscillator anode electrodeseach comprising a plurality of rodlike elements, said oscillator anodeelectrodes being positioned on opposite sides of the first control gridbetween the side rods of the first and second control grids, auxiliaryelectrodes comprising a plurality of rod-like elements positionedbetween the oscillator anode electrodes and the second control grid, andan electrical connection between the first control grid and saidauxiliary electrodes, the rod-like elements of each of said oscillatoranode electrodes lying in a plane perpendicular to the plane passingthrough the cathode filaments.

5. An electron discharge device having a cathode surrounded by a firstcontrol electrode. a second control electrode and an anode, oscillatoranode electrodes lying between said first and second control electrodesand each of said oscillator anode electrodes comprising a plurality ofrodlike elements lying in a common plane transverse to an axis of saidelectron discharge device and lying on opposite sides of the firstcontrol electrode, an auxiliary electrode positioned between each ofsaid oscillator anode electrodes and the second control electrode, saidauxiliary electrode elements comprising a plurality of rod-like elementslying in a common plane transverse to the planes passing throughrod-like elements of said oscillator anode electrodes.

HENNY COHN.

